Fluid machines such as fluid compressors or expanders of the single screw type, also known as monoscrew or globoid types, are well known in the art. The single screw of such machines comprises one main rotor usually working with a pair of gate rotors. The main rotor typically has six helical-like flutes each with a globoid or hourglass root profile. The gate rotors each typically have a plurality of radially spaced gating teeth and are located on opposite sides of the main rotor and mesh with the flutes. When the main rotor is rotatably driven, the meshing side rotors are driven thereby and cooperate therewith to displace the fluid fed into the rotor flutes while changing the volume thereof. In the case of compressors having such main and gate rotors in air conditioning or refrigeration systems, the vaporized refrigerant is compressed and transmitted as a high temperature and high-pressure vapor to the condenser.